The present invention is related to thermal control systems generally, and more specifically to thermal control systems including heat pipes.
Fuel cells convert chemical energy to electrical energy and, as a byproduct, waste heat that must be rejected. The power levels and fluxes of a cell are typically low, but the surface area is large. Also, because fuel cells are often included in stacks of several cells, the surface area requiring heat transfer is substantial. This causes a problem if conventional heat pipes are applied to this class of cooling task. The fluxes and power levels are typical of the capacity of an inexpensive three-millimeter heat pipe. However, because the heat reject area is large, and it is necessary to cool at least every other cell in the stack, the number of conventional heat pipes needed grows rapidly. In addition, the conventional heat pipes require a mounting plate or spreader to maintain alignment and to effect heat transfer from the fuel cell components. As a result, conventional heat pipe solutions are often not cost effective.
Conventional fuel cell designs use a pumped oil loop to cool the fuel cell stack. Although pumped oil meets current performance needs, it has several disadvantages. Oil is a combustible fluid and is not environmentally friendly. An oversized pump is required to push the oil through the fuel cell at lower temperatures (e.g., during winter), when the oil""s viscosity increases. Further, a pump has many moving parts that may break and require maintenance, increasing costs.
An alternative device suitable for removing heat from objects having large surface areas is desired.
The present invention is a heat pipe assembly, comprising a base plate and a corrugated lid joined to the base plate to form a plurality of tubes therebetween. Each of the plurality of tubes forms an envelope of a respective heat pipe within the heat pipe assembly.